A recent study conducted by researchers from the University of Minnesota found some unsettling information about cell phone hackers. Researchers discovered that a hacker can track the location of a person and listen to messages without the user’s knowledge – and it is not difficult or expensive to do so.

The hacker could use a cheap phone and easily accessible equipment to listen to broadcast messages via cell phone towers.

“Cell phone towers have to track cell phone subscribers to provide service efficiently,” said Dennis Foo Kune, who worked on the study. “For example, an incoming voice call requires the network to locate that device so it can allocate the appropriate resources to handle the call. Your cell phone network has to at least loosely track your phone within large regions in order to make it easy to find it.”

The researchers, computer scientists from the school, were able to test this by using a cheap phone and open source software. They put their theory to the test and were able to track a test subject within a 10-block area from where they were walking around. The researchers then discussed the possible problems that could arise due to the availability of this information.

The information from this study was presented at the 19th Annual Network and Distributed System Security Symposium in California.

“Agents from an oppressive regime may no longer require cooperation from reluctant service providers to determine if dissidents are at a protest location,” the researchers wrote in the paper. “Another example could be thieves testing if a user’s cell phone is absent from a specific area and therefore deduce the risk level associated with a physical break-in of the victim’s residence.”

A number of people may be worried about the likelihood of a hacker logging into their smartphone or their phone getting stolen. However, cell phone tracking software can help if there was a theft, as the person would not only be able to identify where the phone was, but they would also be able to see everything that the person did while they had the phone.